Maximizing the benefits of Wind Energy

Energy system planners face a challenge in wind energy’s variability: the electricity flows only when the wind blows, and that may not coincide with peak demand periods. Strong winds in the middle of the night, for example, will produce plenty of current but most people are sleeping so power consumption is low compared to other times of the day.

In an integrated power supply network that includes alternative energy, planners will rely on a mix of conventional generation technologies. The energy produced from each source then feeds into the web of transmission and distribution lines, which is controlled by a system operator that matches production with demand in its coverage area. There’s a “base load” supply (i.e., the minimum amount required at any time) and then planners can adjust the output of the system by regulating conventional power plants such as hydro, a more flexible generation source, to complement the electricity flowing in from alternative sources.

As the wind industry grows, scientists and wind energy advocates will need to find ways to develop more efficient systems of storing wind energy that is generated during times of low demand. This will become especially important when wind-generated electricity provides a more significant proportion—20% or more—of Canada’s power supply. On small-scale residential turbines, the current can be fed into a rechargeable battery, for later use. Hydrogen researchers at the University of Toronto have also devised ways to marshal a turbine’s electrical current to create compressed hydrogen for use in the fuel cells that may some day power cars.

Another innovation under development is a process for coupling turbines with compressed air. The electricity drives a compressor, and the pressurized air can then be stored for future use in running a generator.

In jurisdictions with hydro dams, there’s another possible means of storing wind energy. A hydro-electric station’s electrical output is controlled by the water levels in reservoirs behind the dam. When more power is needed, water is pumped into those reservoirs. If wind turbines can be coupled to such hydro stations, the electricity can be used to run the pumps. In effect, the wind energy is “stored” in the reservoir in the form of higher water levels, and can be used when electricity demand is high.